(a) Field of the Invention
The present invention relates to a slow charging method of an environmentally-friendly vehicle and an on-board charger using the same, and more particularly, to a slow charging method of an environmentally-friendly vehicle and an on-board charger using the same that can improve charging efficiency and thus save a charging cost by changing charging output of the on-board charger based on a temperature thereof.
(b) Description of the Related Art
As is well known in the art, environmentally-friendly vehicles including an electric vehicle, a plug-in vehicle, etc. are driven by utilizing power of a motor operated by battery power. Such environmentally-friendly vehicles may he applied with a plug-in charging method that charges a battery with an external commercial power supply. In the environmentally-friendly vehicle, an on-board charger is installed to rectify the external commercial power supply and to provide slow charging for plug-in charging. The charger installed in the environmentally-friendly vehicle requires additional packaging due to the added elements of the charger which include a high voltage switch, an inductor, a capacitor, an insulated transformer, and a cooling system.
Further, since respective parts forming the charger are expensive and heavy in weight, increased cost and low fuel efficiency of the environmentally-friendly vehicle may occur due to the increased weight of the charger. The environmentally-friendly vehicle including the on-board charger, for example, is charged, as shown in FIG. 1, in an electric vehicle charging station 10. The electric vehicle charging station 10, as disclosed in the related art, may include a fast charger 11, a slow charger 12, and an electric vehicle charger 100. The electric vehicle charger 100 may be configured to adjust the charging time of the respective chargers 11 and 12 to satisfy charging time requirements of various environmentally-friendly vehicles.
According to the electric vehicle charging station 10 in the related art, a charging method is provided at a minimum cost by implementing a fee for charging power, and a usage fee for using the charging infrastructure, but the charging method cannot be usable at the charging station without the electric vehicle charging station 10 since the on-board charger installed in the vehicle does not adjust the charging. Thus, the electric vehicle charging station 10 in the related art is usable only when it is installed in each charging station, and therefore inconvenience and inefficiency are inevitable when using the electric vehicle charging station 10.
Meanwhile, when charging the battery using the slow charger of the environmentally-friendly vehicle, a higher energy fee is incurred for battery charging energy since efficiency of the on-board charger cannot be 100% when charging the battery. In other words, when the battery is charged using the slow charger, the efficiency deteriorates due to thermal loss of the on-board charger itself, and therefore a higher fee is incurred for actual charging energy. For example, the battery charging energy is about ab.1 kWh (a, b): integer) when charged by the on-board charger with charging capacity of about x.6 kW (x is integer), but when the battery charging energy is about cd.9 kWh (c, d: integer, cd>ab), a user of the environmentally-friendly vehicle is required to pay a charge for cd.9 kWh, which is the energy used by the on-board charger.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.